Process for incorporating metal in resin structures



2,264,003 PROCESS FOR INCORPORATING METAL IN RESIN STRUCTURES Nov. 25, 1941. w. OSENBERG Filed Dec. 24, 1937 2 Sheeits-Sheet 1 WW n Nov. 25,1941. w. OSENBERG PROCESS FOR INCORPORATING METAL IN RESIN STRUCTURES Filed Dec. 24, 1957 2 Sheets-Sheet 2 f g, f v MM assist Nov. 25, i 94i 2,264,003 Faocsss Foa mcoaroaarmg am'rar. m

328m STRUC Werner Osenberg, Dresden; Ge

Application December 2i, 1937, Serial No. 181,862

Electrical outlet elementsare usually made. with a baseor carrier and electrical conducting parts mounted thereon, such, for instance, as screw sockets for light bulbs, tubes for radio devices or the like or plug-in sockets and switch a parts foroutlet boxes, plugs for the corresponding outlets, contact tongues and the like. The carrier is of non-conducting material, for instance,a ceramic mass. I

The practice of forming electrically conducting parts on. a non-conducting carrier is known, which consists, in general, to apply a conducting metal layer immediately upon the carrier and chiefly upon correspondingly formed projections, depressions or the like, for which purpose, the familiar spray process is particularly suitable, such as the Schoop metal spray process.

If, the carrier is of ceramic material, the sprayed on thin metal layer will adhere in practice with sufficient security, because the surface of the carrier .has a certain roughness which is favorable to such adhesion and the ceramic material, can easily withstand the heat of the sprayed on metal without alteration in the constitution of its surface. In many cases, however, the carrier is of synthetic material, as for instance, synthetic resins, cellulose plastics or the like, in which case, the carrier is produced in a mold or can be cast or sprayed into the mold.

Such carrier bodies have the corresponding smooth walls of the mold and their surface is plain and smooth so that a sprayed on metal. layer will not adhere-securely thereto. Moreover, the surface of carrier bodies thus formed is not sumciently resistant to the temperatures 35 occurring in the spraying process, so that in practice, alterations will occur in thesurface of the carrier, which lead to detachment of the sprayed on more or less thin metal layer, which is, of course, objectionable, since-it is vital that so the conducting layer on the carrier body must by all means be lodged tight if the electric element is to accomplish its purpose. According to the present invention, these objections are overcome body and strips readily from the wall of the mold.

- The adhesion to the carrier body isipromoted by the expedient that the metal layer in the mold Wall has the side thereof facing the carrier ex- "66' traordinarily rough and therefore, becomes in timately combined with the molded material of the carrier body; the release of the metal layer from the mold wall is promoted in that the mold wall is entirely smooth and to further promote such release, the wall of the mold, may prior to application of the metal layer be treated with grease, graphite or the like.

In the drawings: I

Fig. 1 is a diagrammatic view in longitudinal cross-section indicating the mold, the stenciland the nozzle in alignment,

I Fig. an a view slmilar to Fig. 1 illustrating the mode of spraying the metal against the wall of the mold,

Fig; 3 is a view similar to Fig. 1 illustrating the operation of pressure molding the resin or plastic in the mold,

Fig. 1, is a view in longitudinal cross-section of a modified form of mold with the metal contact sprayed thereinto,

Fig.5 is a view similar to Fig. 4 of a modification, 1

tion thereof, 7 a

Fig. 9 is a view in longitudinal cross-section of.

a modification of the embodiment shown in Figs. 4 and 5, v

Fig. 10 is a view in longitudinal cross-section illustrating the format'mnof a sprayed metal socket in the molded mass,

Fig. 11 is aview similar to Fig. 10 showing the alternative mounting means formed by the process set forth, I

. Fig. 12 is a view in longitudinal cross-section a metal in a showing the formation of molded carrier,

Fig. 13- is. a view in longitudinal cross-section showingthe method of forming two sprayed metallic connected contacts by the method set v forth,

Fig. 14 iim alternative embodiment of Fig. 13,

- Figs. 15,16 and 17 show views in longitudinal cross-section of alternative embodiments in which a flanged metallayer may be' prepared by" the new method set forth.

Fig. 18 is a view in longitudinal. cross-section through the mold With'the introduced molded body, taken insofar as the mold piece is concerned along the section line l8-I8,

Fig. '19 is a fragmentary view in horizontal cross-section through the completed molded body taken on line l9l9 of Fig. 18, I

Fig. 20 is a fragmentary view in longitudinal cross-section on an enlargedscale of the mold with the finished apparatus in place therein,

Fig. 21 is a plan View of the floor of the mold,

Fig. 22 is a perspective view of a radiosocket, the method of forming which is shown in .Figs. 17 to 21 inclusive,

Figs. 23, 24 and 25 show diagrammatic views in longitudinal cross-section of alternative arrangements for applying molten metal by pour- ,ing. directly into the mold.

InFig. l a mold is shown with a cavity 2 rectangular in cross-section, a stencil'3 with an undercut spray opening 4 and '.a spray nozzle which is part of a metal spraying apparatus sion is simultaneously produced therewith in the bottom of which the conducting layer 1 will be of any desired form. In Fig. 2 it is shown how' the plate 3 is laid upon the floor of the spraying mold and how the spray nozzle 5 correspondingly disposed with respect to the spray opening, hurls the metal spray jet 6 against the stencil 3. The undercutting of the spray opening 4 brings about the result that a metal layer 1 deposits upon the floor of the mold, which forms structurally completely separated from the stencil. As a result, the stencil may be readily removed from the mold after completion of the layer I. The metal 8 which deposits at the borders of the stencil opening 4 in the spraying process may be readily scraped off said stencil after the latter has been removed.

The mass is now introduced into the mold as shown in Fig. 3 of which the carrier body is to be formed. In this embodiment, it is assumed that a pulverulent mass of synthetic resin is being used, which is to be shaken into the mold and that thereupon the pressure die 9 is applied with suitable heating of the mass to between 140 and 160 degrees C. and with the exertion of a pressure of 400 to 600 atmospheres, whereby the mass is shaped, first entering into a fluid and then passing into a solid condition in manner well known. In this operation, the metal layer 1 which is on the floor of themold combines intimately with the mass of the carrier, since its rough surface ll faces the carrier. In the removal of the completely formed body, the metal layer will readily rise from the smooth mold wall and at the corresponding surface of the carrier a place is afforded which is provided with an electrically conducting layer embedded in the carrier. While in the process shown in the embodiments of Figs. 1 to 3, the conducting layer is bonded to the surface of the carrier, the embodiment of Fig. 4 shows the floor of the mold provided with a depression ll into which the metal layer is sprayed in such manner as to cause such layer to protrude above the floor of the mold and so protrude from the depression.

cil 3 must have a corresponding form which in the case of a-depression of rectangular crosssection, must be U-formed and afiord two undercut spray openings 4. The lower part of the stencil is reduced as at l3, so that the stencil in its removal may pass the conducting layer applied to the wall. The adhering conducting layer I formed on the walls of the mold are securely gripped in the shaping and flowing of the plastic mass under high pressure. To avoid displacement of the layer 1, steel rods M are set into the wall mold, which protrude slightly from the wall of the mold and at their ends extend into the sprayed-on layer 1. These rods securely.

retain the layer 1 in position during the molding operation, and prior to removal of the mold body are drawn outward. The small holes thus formed upon the surface of the metallic layer are not objectionable in practice.

Although, in general, the metal layer formed upon the smooth wall of the mold is readily releasable therefrom, especially when the mold is treated with grease or graphite or the like, it is yet advantageous in many cases to provide special means for further promoting the release of the sprayed sheath from the mold wall. In the embodimentof the process shown in Fig. 7, a die l5 protruding through the mold wall serves 'as a release means. The end surface l6 of this die lies flush during the spraying on of the metallic layerwith the surface of the mold wall, in this case the floor of the mold. Upon completion of the molding of the carrier, the plunger is moved to the interior of the mold and thereby aids the removal of the molded body from the floor and the release of the metal layer I from th wall. of the mold respectively.

Another method serving for the like purpose is shown in Fig. 8 of the drawings. Here fine air canals I! are provided at the corresponding portion of the mold wall vthrough which after the molding of the body, compressed air is blown whereby the release of the metal layer 1 with respect to the mold wall is advanced. In practice the atomized metal will not enter the air channels in the spraying operation, if the latter are correspondingly line, that is, corresponding small diameter.

In order further to enhance the adhesion of.

the metal layer I to the wall of the carrier, it'is possible, as shown in Fig. 9, loosely to introduce the mold body is then formed, it will upon com-- pletion, ail'ord at its surface a conducting layer 1 in the form shown, raised above the surface of small metal rods ll into the wall of the mold or into small bores therein respectively; such rods protruding to the interior of the mold and bein: of length such that they may protrude forward beyond the sprayed on metal layer I. These rods become anchored in the molded mass of the carrier body and thereby aiford a secure seat I for the metal layer 1 at the surface of said carrier body. The ends ll of the rods which protrude beyond the metallayer I after removal of the completed molded body, which-previously were lodged loosely in-rthe openings of the mold wall,

v but also upon the part 2! Fig. 12' may be fouowed.

may readily be removed by filing. clipping shearing oil. i

In Fig. is shown an embodiment in which conducting parts with a predetermined bore, may readily be produced directlyon the molded carrier body according to the new a core piece 23 is introduced into the wall of the mold (in the embodiment shown in the door process. In this case,

, In the process according to Fig. 14, the same result is accomplished in that a metal'bail It is disposed upon the floor oi the mold i, which 01 mold i), the threaded part 2! oi which protrudes into the mold and through the opening 4 in the stencil 3. In spraying, a metal layer is formed not only upon'the wall or the mold,- of the core piece 20, which protrudes into the mold. It now, after-removal of the stencil 3, the molded body is pressed in the mold, the metal layer part I becomes embedded therein and affords "a, tapped interior. The core piece may now be removed by unscrewing, and the completed carrier body is thus provided with a conducting part in which the threaded socket oi the lamp be screwed in.

In the embodiment shown in Fig. 11, the core piece 20 introduced into the wall of the'mold, is shown with an enlarged or bellied part 22 proiecting into the mold. In the application of the spray process, a metal layer 1 forms about said core piece, which interiorly corresponds to the bellied portion 2i. In this case the material. which is prepared, for instance, of plaster-oh- Paris, wood or the like, may be readily removed from the completed unit by breaking-and destroyor radio tube may upon spraying on the metal layer 1 through the 1 opening 4 or the stencil 8 becomes combined with the layers and subsequently in the production of the molded body will become lodged therein.-

In Figs. 15 to 17 is shown a method by which metal layers '1 may be provided on the molded body or projections I aid oi. the new process and in which the layer in the .iorm of a cap superposed over the body. v

Where, in the illustrated examples, the mold is rectangular in proille, it is possible, known to produce bodies of desired profiles by molding, spraying or casting respectively, in particular where compound molds are "used. The new process renders possible to provide a conducting metallayer on any selected part of a carrier body, with the duced in a mold form.

For instance, in Figs. .18 to 21 is shown the apparatus a shown in 22. In this socket projections 21 are to be provided with tongue formedmetal terminals. For

ing the same. There is producedin the molded body, a depression of predetermined contour provided withan electrically conducting coverin into plementary contour-may be introduced thereby to aflord acontact. t

. It the molded carrier body is to be provided with a bore therethrough the wall of which is to havea conducting lining, the process shown in Inthis case a plunger 23 is used, which penetrates the molding die proper shown at 9, as well as the massjintroduced to be molded and extends into thewall special matings or the mold I it is possible to floor of the mold with the aidooi the stencil, but the plunger Illitself may be surrounded by a metal layer i up to a desired level. Aftercompletion of the molded and removal or the plungerfl, this body is round to have abore lined with a-conducting layer 1 in which this conducting-layer protrudes overthe molded body, whereby this conducting lining in the molded body, protrudes ,atthe lower end that rests againstthe wall'of the'mold.. q v Frequently. it is-necessary that spaced con.- ducting layers on thecarrier body are to be conductively connected to each other. In the process jsho'wnin Fig. 13, that resultis-accomplished as follows: The metal layers lwhich are'to .be conductively ,connectedby the spraying process are formed on the wall or the mold (in the illustra tive' embodiment on the door of the :mold);

'I'hereupon aislide, piece 28 is introduced between In executing the spraying process,

molded, whereby it takeswhich an element having tongues with comv this purpose, a two-part mold is utilized composed ofparts l-A and i-B. In the 'moldpart 5-3 there are depressions 28 which correspond,

to the form of the tongue and the metal is sprayed thereinto. The tongues are'provided with tubular studs, by mean of tore pins introduced into the mold, whichlstuds become lodged in themas's to be molded. the material is-slven' the desired form by means of. a correspondingly. contoured pressure die, whereby the, molded material becomes intimately combined with the tongues l and at the same time conductively lined bores 3| are formed for the introduction of electrical conducting wires;

produce a metal layer 1 upon the through-the mold with Fig. 18 shows .a longitudinal w cross-section introduced molded mass.

Attention should alsolbe called to the fact that the walls of the mold may also be provided with such as chromium, for instance, in order to enhance its smoothness and thereby to facilitate the covering. .1 In the spray process, the sprayed on layers may thereof respectively with the asis'well desired profile and ln'the composite mold,

ready: release of the sprayed on be of such thickness asdesired; they may, for

instance, be'made sothick that they are capable of solderconnection of other parts thereto.

- r 0f course,.it i possible to apply diderent'metals by the spraying procedure for variousflmetal parts to be disposed onone and thesame carrier, whereby, if desired, the different coloring. of the metals may SOI'VB'ifOI'dlSflHEillShiDE the same.

-; Furthermore, the'new process permits theprovision oi metal layers not onlyat thewall of the mold, in order to introduce the same upon-the molded body, but such-,metal coatings am'ay..-be

provided onrthe die or plunger: it'seli'. Thus, 'Eit' is possible thereby-toqprovide a moldedbody'iin' and finally the bridge 250i conresortto the new process. 11

Onthe other hand, it ispossible tor-introduce. metallic conducting parts I ,even in the; interior of the molded body, if such molded body;,- bythe aid of a plunger or die'is formedasa hollow body.- For instan e,&in the embodiment-of plunger?! this manner with a complete, metal covering by.

s o n inris s r ue em t l y zlf may, e rov de io h s sj y' r t-.tca esnrey procedure, which; after completion of the molding operation, are transferred to the molded body, that is, they remain adhesively connected 1 to its inner wall 3| and serve to provide the conductive connections with the hollow studs 30.

While in the .preceding description, it has throughout been assumed that the conducting metal sheath is produced upon the wall of the mold by aid of the known metal spray proceding,

the metal sheath could be produced in other manners. For instance, as shown in Fig. 23, it is possible to provide upon the floor of the mold l a stencil 32 of suitable material with an opening 33. Into this opening, th fluid metal may be poured. In cooling the metal layer in the opening 33 shrinks, so that the stencil 32 may be lifted out, while the metal layer remains adhesively connected to the floor of the mold; thereafter the process is completed as in the other embodiments.

In the embodiment of Fig. 24, a depressed opening 33 is provided in the floor of the mold I, so that the use of a stencil 32 is unnecessary, since only the opening 33 need be charged with fluid metal. I

In Fig, is shown a process for producing the I product shown in Fig. 12 by casting rather than spraying and this by resort to a mold 34.

While the various applications shown in the drawings are particularly concerned with elecsame to the forming and hardening treatment, in which latter operation the metal body will be securely bonded to the molded body and to the insert and will become readily released from the smooth mold wall.

4. The process recited in claim 2 in which the stencil opening or openings are undercut in order to avoid adhesion of the metal deposited in the mold with respect to such metal as is deposited upon the stencil.

5. The process of"forming a molded body of synthetic resin, with a metal socket bonded therein, which consists in introducing into a trical apparatus; it is understood that the method is useful in a wide variety of other applications, as, for instance, in the preparation of ornamental door knobs, window grips, oranmental buttons, vessels, pails or the like, each of which may be primarily of molded synthetic resin or the like,

and may be wholly or partly covered with metal previously introduced into the mold at localized places or'over the entire area thereof as indicated.

I claim:

l. The process of incorporating a metal body with a portion ofthe surface of a smooth insulating body of hardened resin, which consists in forming the metal body by spraying the metal in molten condition in a corresponding portion of a smooth surface mold with consequent rough surface of the metal when congealed, introducing and forming the resin in the mold, then withdrawing the formed body from the mold with the metal bonded thereto at the unfinished upper surface thereof.

2. The process of incorporating a metal body with a portion of the surface of a smooth insu-' lating body of hardened resin, which consists in introducing into a mold and against that portion thereof corresponding to the metal body, a stencil plate, spraying molten metal into the mold through said perforated stencil to the desired thickness, removing the stencil, introducing the resin into the mold, subjecting the same to the forming and hardening treatment in which latter operation the metal body will be securely'bonded to the formed body by reason of the roughness of thesurface of contact and the composite body may be readily released from the smooth mold wall.

a 3. The process of incorporating a metal body with a portion of the surface of a smooth insulating body of hardened resin,which consists in introducing into a. mold and against that portion of the mold to which the metal is to be applied, a stencil plate and also an inse'rtsurrounded by said stencil plate free from contact therewith and protruding beyond saidstencil plate, spraying molten metal to the desired thickness into the mold through said'stencil plate-and upon said insert, removing the-stencil plate, introducing the resin into the mold, subjecting the mold, a core piece complementary to said socket, depositing molten metal about said inserted piece, to the desired thickness and after hardening of the latter, introducing the' resin into the mold, forming and hardening the same, removing the formed body from the mold, and separating the core piece from the metal deposited thereabout.

of plates to be formed, spraying molten metal through said stencil openings about the protruding ends of the rods and to the desired thickness,

removing thestencil plate from the mold, introducing the resin into the mold, forming and hardening the same, withdrawing the rods from the plates formed thereabout and then removing the formed body with its adherent metal plates from the mold.

8. The process of applying a metal element on a portion of the surface of a smooth insulating body of hardened resin, which consists in introducing small metal pins into the floor of a mold to protrude upward into the body thereof at the region where a metal plate is to be provided in the mold body, applying a stencil plate into the mold, spraying the molten metal into the mold about the upwardly protruding ends of the pins,

removing the stencil plate, introducing the resin .and forming it to become securely bonded with respect to the upwardly protruding pin ends and the metal plate, removing the molded body with its adhering metal element from the mold and breaking on the outer ends of thepins that protruded into the mold floor during forming.

9. The method of forming a metal socket with a multiplicity of metal contacts thereon, which consists in forming depressions corresponding to the metal contacts, in one mold element, as well as protruding pins corresponding thereto, de-' positing molten metal into said depressions'and about said pins, to form the contacts and the mounts thereof, superposing a complementary mold, introducing resin material therein, applying a plunger to pack the resin material in the -form of a socket shell for intimate engagement at its floors with respect to the metal contacts and the metal depositei labout the pins, and withdrawing the same from the mold.

' 'wnnmm oenunnao. 

